100ekW main generator set placed transversely instead of longitudinally?

Could you think of any negative points or cons of placing a 100ekW main generator set placed transversely instead of longitudinally?

 

I have seen many generators on motor yachts of different sizes that are aligned transversely rather than longitudinally.

What type / size of vessel are you intending to fit this generator to?

 

Possible lubrication failure due to lurching.

 

It is pretty common to mount generators transversely. You can mount them wherever is more convenient.

 

And who says it's not normal? The issue under discussion is what are the pros and cons and whether these can be greater than those.
In my country, at least for fishing boats up to 24 m in length, the Administration finds it difficult to accept the transverse arrangement.

 

It would be for a 15m workboat with electric twin thrusters (no propeller shaft arrangement).
To me placing the generator transversely sounds counter-intuitive, non-standard, out of place somehow, but I would like to know why.
I thought about the effect of angular momentum on the wrong direction of the engine moving parts having an effect on vessel motions. And issues with the structure. Will ask Genset supplier.

 

What will be the power output of this generator?
I am guessing it will be rather substantial, as it will be powering two electric motors on a 15 m. workboat.

If you have the space in the engine room to mount it longitudinally, then the two substantial engine beds / girders will form a useful part of the structure of the boat - you would probably still need them anyway even if you mounted the generator transversely.
Why do you (maybe) want to position it transversely? Is it for space reasons in the engine room?

 

Hi. The maximum rated power output of this generator set is 99ekW (but the question is generic to any size)

It's the client who's asked this question about placing it transversely (to save some boat length), I don't like the idea. And I am looking for reasons why is better not to do it.
My preference is to place it longitudinally as usual.

 

All you need to consider is the trim/heel and the roll/pitch of the vessel under various static loading and then in a seaway dynamic loading, to ensure the genny is not starved of fuel.
From either the fuel tank end or the at the genny end; it allows remains positive.

We mount all our genny's transversely.
Saves space, easier for maintenance and easier to mount.

And...for a vessel of your size, if you mount long.t, you will most likely have to have deck beams cut for access hatch. In general, you can avoid this when mounted transversely, as the width of the genny is less than the frame spacing.
So it can also have structural implications too.

But no hard fast rule...

 

What do they find "difficult"....and does that mean they will or will not?

 

@ram68ocean can you maybe post a plan view sketch or drawing showing your proposed engine room arrangement?
Where would the generator be relative to the two electric propulsion motors?

Is this a retro-fit to an existing boat, or is it a completely new design?

 

Yes, there are some potential downsides to installing a 100 kW generator set transversely instead of longitudinally. A transverse layout can reduce maintenance access to key components like filters, the alternator end, and belts. It may also complicate cooling airflow, increasing the risk of recirculation or hot spots that could lead to derating. Exhaust routing can become longer or tighter, adding backpressure. Vibration loads and mounting requirements may change, requiring extra structural consideration. Plumbing for fuel and oil drains can be less straightforward, and noise control may be more difficult if loud components end up closer to occupied areas. Finally, some manufacturers specify orientation limits, so warranty approval should be checked before installing.

 

We've installed gennies transversely on pretty much all our vessels from circa 10kW to well over 100kW.
Never had any issues that you cite.

 

No.

Can you list any advantages in your case?

 

I completely agree with @starcmr. In fact, Spanish maritime authorities, at least for fishing vessels under 24 meters, have been "advising" against transverse placement of generators for years.